In recent years, the acceleration of informatization in school education in Japan has necessitated support mechanisms that allows children to understand their own learning status and adjust their learning autonomously by utilizing learning histories. However, in mathematics education, which is strongly connected to prerequisite knowledge, it is difficult to objectively identify where weaknesses arise. Therefore, it is considered increasingly important to provide learning support that enables students to understand their own comprehension status and to decide on the next learning units or problems to tackle. In this study, we propose a method to support learners in identifying their learning weaknesses and selecting problems to work on in mathematics education by marking the weakness level and subjective comprehension status on a Task Analysis chart. The implementation of this method in high school classes showed that considering subjective comprehension status allowed students to recognize areas of uncertain understanding and gain new insights into their learning weaknesses. Additionally, displaying the weakness level on the Task Analysis chart was suggested to be helpful in deciding which problems to work on next.